High-frequency phase shifters are used for example in antenna technology for phase-controlled antennae to swivel the radiation pattern or to shape it. In this case there is usually the requirement to enable swivelling of the radiation pattern electronically. This leads to the demand for a high-frequency phase shifter which is electronically controllable in its transmission phase Φ.
A phase shifter for electronic variation of the phase is known from DE 3802662A1. This consists of a series phase shifter assembly, the range of variation of the individual phase shifters being small. The phase is in this case varied by means of switched diodes. For continuous tracking of the radiation pattern of an antenna, however, it is desirable to vary the phase continuously, i.e. in analogue fashion, by means of an electrical signal. A phase shifter which is variable in the transmission phase Φ electronically and in analogue fashion is known from DE69127128. The phase shifter consists of a four-terminal hybrid circuit with a branch line connected to only two variable-capacitance diodes or varactors of which the capacitance value is varied by means of a control voltage. A structure of this kind is admittedly able to sweep a large angular range of the phase, but with only two variable-capacitance diodes it does not allow appropriate compensation of the influences, to the effect that, on the input and output sides, adequate reflection loss is achieved in relation to a reference characteristic impedance Z0 on the input and output sides.